616 



Popular Science Munilily 



Making a Polisher for Table Cutlery 

 from a Piece of Carpet 



AN efficient cutlery polisher, as here 

 . shown, is easily made from a small 

 board and a piece of carpet. To a board 

 about 6 in. wide, 8 or lo in. in length 

 and an inch in thickness, with both long 

 edges quarter rounded, is tacked a piece 



Powdered brick is sprinkled between the 

 layers and the articles are rubbed over it 



of carpet to entirely cover the board on 

 one side and extend over the rounded 

 edges. Over this carpeted board is 

 placed another piece of carpet the same 

 size as the board, but tacked fast only on 

 one end. The nap surfaces of the two 

 pieces of carpet should face each other. 

 Sprinkle a little cut bath-brick between 

 the layers, moisten knife or fork and 

 rub in and out, as shown in the illustra- 

 tion. — John Hoeck. 



How to 



Make Your Watch-Dial 

 Luminous 



Till' first tiling to do is to procure an 

 ounce of calcium sulphide, lumin- 

 ous. The cost since the war is one dollar 

 an ounce, but you can fix perhajis fifty 

 watches with lliat amount. This ele- 

 ment absorbs light, and after being ex- 

 posed to any bright liglit for five min- 

 utes will glow with a purple light for 

 about four hours. 



Remove the cr\'stal fidni the watcli 

 to i)e treated, and willi a pen dipped in 

 shellac go over the numerals and the 

 hands. Some may prefer to make dots 

 onh' at the numerals. Pour out the 

 calcium on a cle.ui piece of paper, clip 

 your finger in it and |)ress some on tlu' 

 moist shellac. Allow about five minutes 

 for it to dry. The calcium not used 

 may ije returned to the bottle. 



Some Peculiarities of Different Styles 

 of Eye-Glasses 



WP2ARERS of eye-glasses often give 

 offence to persons whom they 

 meet in the street by looking, and 

 apparently staring at them obliquely 

 in a seemingly critical manner. 



The offenders are usually near-sighted 

 persons, who wear the old-fashioned 

 biconcave glasses^, and who ha\e ac- 

 quired a habit of looking obliquely at 

 approaching persons, because they are 

 thus enabled to recognize them at a 

 greater distance. This peculiarity does 

 not seem to be generally known. Far- 

 sighted persons, on the contrary, see 

 less distinctly when they look obliquely 

 through their eye-glasses, if these are 

 of the old biconvex form. 



The strength of an eye-glass is 

 inversely proportionate to its focal 

 length and is reckoned in units called 

 diopters. A glass of one diopter has a 

 focal length of one meter, a glass of two 

 diopters has a focal length of one-half 

 meter, and so on. As one meter is 

 nearly equal to 40 inches, the focal 

 length in inches, according to which 

 eye-glasses are still occasionalh' classi- 

 fied, can be obtained by di\ itling 40 by 

 the dioptric number. 



The elTecti\e strength of an eye-glass 

 of the old flat form, whether conca\c 

 (Fig. 1) or convex (Fig. 3) is slightly 

 increased and the distinctness of vision 

 is slightly impaired by looking obliquely 



The old flat and convex forms of eye-glasses 

 and the meniscus, or periscopic, glasses 



through I 111' perii)lu'ral portion. These 

 (H'ciiliarities are nearly eliminated in 

 the newer meniscus or periscopic glasses 

 ([■'igs. 2 and 4). For far-sighted persons 

 the new curved glasses are always to 

 be reconnnended. Man\- near-sighted 

 persons, on the contiary, |>refer eye- 

 glasses of the old Hat type, which give 

 them distinct direct vision of objects 

 at a moderate tiistance. 



